American children are routinely vaccinated against pertussis, a severe cough commonly called whooping cough. Caused by the bacteria Bordetella pertussis, the condition acquired that moniker as patients sometimes exhibit a sharp breath intake resembling a “whoop”. Pertussis is extremely contagious and can be fatal in newborns, making it a serious health concern. Vaccination appeared to have eradicated it in the U.S., until health officials in California reported a pertussis epidemic in that state, starting around 2009.
Whooping cough could be re-emerging for two reasons. First, it could be due in part to some parents’ decision to opt out of childhood immunizations, despite ample evidence that vaccines are safe and protect children and adults from devastating diseases.
Another could be differences in potency between the old versus new pertussis vaccines. In the 1950’s children were vaccinated with what was known as the wP (for “whole-cell”) vaccine, which was highly effective but gradually phased out due to rare side effects. By the mid-90’s wP had been replaced with what is called the “acellular” (aP) pertussis vaccine, which is not as long-lasting or potent as the wP version. Many of the recent cases of whooping cough occurred in American teenagers vaccinated with the aP vaccine.
These differences are prompting scientists in the lab of LJI vaccine biologist Alessandro Sette, Ph.D., to compare aP and wP vaccines in terms their molecular constituents and evaluate differences in T cell responses seen in individuals vaccinated with each.
Sette predicts that the different vaccine groups may show unique T cell responses, with one scenario being that the wP vaccine elicits a more potent T cell response. If so, the goal might be to incorporate selected molecular components, or epitopes, used to construct the wP vaccince into a next-generation vaccine with the safety of the most recent version. So dedicated is Sette to this effort that he and other members of his family vaccinated against pertussis have donated their own blood as samples for comparative analysis.